Exploring magnetic stability and valley splitting on CrI3/SiC van der Waals heterostructure

Abstract

The CrI3 monolayer fabricated from recent experiment has attracted much attention due to its long-range FM order. However, the very low Curie temperature Tc (~45 K) severely limits its realistic application. Herein, we construct the vdW heterostructure for CrI3 with SiC momolayer to explore improvement of magnetic properties. The detailed calculations show that the FM coupling of CrI3 layer in heterostructure can be enhanced with Tc up to 62.3 K, which is attributed to both superexchange interaction and proximity exchange effect. Besides, intrinsically nonmagnetic SiC layer is also magnetized and holds a significant magnetic exchange splitting of valley. More importantly, the magnetic exchange energy is found to be steadily increased with the interlayer gap reduced, making Tc up to 128.8 K, and the external electric field enhances the heterostructure FM coupling as well, with Tc reaching 93.14 K. This is because the superexchange interaction and proximity exchange effect are intensified by physical field coupling on the heterostructure. We also observe that the magnetic exchange splitting of valley causes the noticeable half-metal feature upon the electric–magnetic coupling. Overall, our findings provide new strategies for improving magnetic stability of two-dimensional magnetic materials and imprinting magnetism into other nonmagnetic materials.